1. Field of the Invention
The present invention generally relates to golf clubs used for training golfers proper golf swing tempo and, more particularly, to golf clubs which have highly flexible shafts.
2. Description of the Prior Art
FIG. 1 shows a traditional golf club which includes a head 10, a shaft 12, and a grip 14. The head 10 can be a wood, including a steel wood or the like, an iron, or a putter. The shaft 12 projects down into the neck 16 of the head 10 and is secured by glue, pins, whipping, or other means. The grip 14 is secured to the top part of the shaft 12 by glue or the like and is generally tapered, and is often made from leather or rubber materials. The grip 14 is intended to provide the golfer with a firm hand hold on the shaft 12. Most golf club shafts 12 are relatively stiff and are made from hollow steel tubes or graphite rods. Many golfers have thought that a golf club with a stiffer shaft 12 can be hit more accurately on the belief that reduced flexing of the shaft 12 enhances the likelihood of the head 10 being in the correct position to strike a golf ball at the bottom of the downswing. In addition, most golf club shafts 12 are tapered from the top 18 towards the bottom 20, whereby flexing of the shaft 12 during a golf swing is accentuated towards the narrower diameter bottom 20. Many golfers have thought that moving the shaft 12 flex point closer to the golf ball, as is done with a tapered shaft, will provide greater control.
It has been well recognized by golf instructors that many of the problems experienced by golfers are related to an improper swing rather than the golf club design. As early as 1928, U.S. Pat. No. 1,662,712 issued to Carl Mensing on a golf club with an extremely limber or whippy shaft. Specifically, Mensing contemplated using rubber, rattan wood, or raw hide shafts on golf clubs. Golfers swinging the Mensing type golf clubs need to use a smooth, rhythmic swing in order to correctly strike the golf ball. If the golfer applies a jerking or quick hitting motion to a golf club with an extremely limber or whippy shaft, he or she will either slice the golf ball or miss it completely. When the Mensing type golf club is swung properly, the golf ball will travel the same distance or further as it would with a normal club because the club head will be moving at the same rate as the club head of a properly swung normal golf club.
The golf club shown in U.S. Pat. No. 1,662,712 to Mensing has a tapered shaft and, therefore, has a flex point below the median region of the club. It was later determined that a higher flex point on the shaft can be beneficial. Specifically, in U.S. Pat. No. 2,250,429 to Vickery a golf club with a reduced diameter medial region is shown. Vickery likened the golf club to a baseball pitcher's arm and stated that flexing at the medial region would be analogous to the pitcher's elbow. Vickery also contemplated reducing the diameter of the shaft towards the club head so that it would behave like a baseball pitcher's wrist. Vickery's club shaft designs have the drawback of requiring additional manufacturing steps in order to create the reduced regions. In addition, the reduced diameter regions of the Vickery club shaft are likely to encounter severe stresses during the golf swing and they may be more prone to failure.
Twisting of the golf club during the swing is a common problem among golfers. A "twist" swing occurs when a golfer twists his or her wrists severely during a golf swing. When the club shaft is twisted, the club head will strike the golf ball improperly and make it unlikely that the ball will fly straight to its target. U.S. Pat. No. 4,580,785 to Toku shows a golf club shaft which includes a metal leaf spring positioned inside the hollow, cylindrical shaft. The Toku golf club provides the golfer with sensor information in the form of vibrations from the metal leaf spring when a golfer executes an improper "twist" swing. Because the Toku golf club is cylindrical, it naturally flexes in its middle region. A particular drawback of the Toku golf club is that the shaft requires several components and would be difficult to manufacture.
The manner by which a golfer controls his or her hands can also lead to several problems in striking a golf ball. For example, applying severe hand effort at the top of the backswing will take the club head out of a good swing groove and will generally result in a poor shot. In addition, premature application of power with the right hand (for right handed golfers) immediately prior to impact will decelerate the club head and cause loss of distance and a shot that goes to the right. Likewise, "wristiness" with a putter can pull the putter head off line. None of the prior art training golf clubs provide any means for a golfer to sense improper hand action as well as tempo and twisting swing problems.